DESCRIPTION: The main objective of the application is to better define the human health risks associated with prenatal and early postnatal exposure to methylmercury in fish. Subtle psychological and behavioral changes will be measured and related to the exposure of mothers during pregnancy. The study will be conducted on a cohort of 740 children from a population in the Seychelles Islands, whose diet consists primarily of large amounts of ocean fish. The application will extend the evaluation of developmental toxicity of methylmercury on the cohort to include the age of 7-8 years, which will make it feasible to compare results with those from studies of prenatally exposed infants in New Zealand and the Faeroe Islands. The population used in the longitudinal study presents a wide range in mercury levels so that the results can be applied in assessing the health risks in the U.S. population due to consumption of methylmercury in fish.